Domestic fuel oil tank of the prior art are usually provided with an outlet tap close to the bottom wall of the reservoir and positioned in one of the end walls. The tap provides a shut-off for the fuel and a connection to a fuel line to supply fuel oil to a fuel burning apparatus. The outlet pipe enters the reservoir above the bottom wall. Accordingly, such reservoirs have been known to accumulate water therein due to condensation, rain or other reasons and these reservoirs are usually mounted outside or in basements of buildings.
Because water is heavier than fuel oil it accumulates at the bottom of the tank and makes the tank rust in that area particularly around the coupling for the outlet pipe and joints. Also, because fuel oil contains an admixture of chemicals it also inhibit rust formation. Some of these chemicals may contain sulfur which when mixed with water acts like an acid and accordingly accelerates the rusting process. Another disadvantage is that as water accumulates and stagnates at the bottom of the reservoir it could eventually reach the level of the outlet pipe and large quantities of water may then flow in the supply line and extinguish the burner of the apparatus being fed.
Another disadvantage of fuel oil reservoir is that they provide an environmental problem in that they pollute the soil. For those reservoirs that are installed inside buildings they usually cause spills on the concrete and the oil impregnates the concrete causing odors and stains which are difficult to remove. Another disadvantage of fuel oil reservoirs is that when installed inside buildings they are often disposed at an angle. Therefore, the feed pipes which connect to the exterior of the building to supply fuel oil to the reservoir need to be bent and this causes solder joints to crack.
The solution to the above-mentioned problems is that reservoirs are being constructed of thicker steel to guarantee a 10 year life. The result of this is that they are heavier to carry and more costly and they do not prevent water from accumulating in the reservoir nor do they solve the problem of the feed pipes as mentioned hereinabove. Most fuel oil tanks are also awkward to transport and manoeuver.